package com.func.boom.utils;

import lombok.extern.slf4j.Slf4j;
import org.apache.commons.codec.binary.Base64;
import javax.crypto.Cipher;
import java.security.*;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

/**
 * @author Yulei
 * @date 2020-09-10 19:06:08
 * @desc
 */
@Slf4j
public class RsaEncrypt {
    /**
     * 用于封装随机产生的公钥与私钥
     */
    private static Map<Integer, String> keyMap = new HashMap<Integer, String>();

    static {
        keyMap.put(0, "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCSNg1Zr8yAtvCCnVkk67CMtPmMBQ2OetaZn0BikuhBgo6wbCaIHR1FHb0gSO05RisnfWnbzzygP1VRUaBoNtfX1HfYL1FqVjFy3+GXEnve7eTZx/s7arr1gNHELNu6ZMLSKswrVMym69gE/dwWYrzKjcUNdoZHhlEjgtsrYRz+BQIDAQAB");
        keyMap.put(1, "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");
    }

    public static void main(String[] args) throws Exception {
        //生成公钥和私钥
        genKeyPair();
        //加密字符串`
        System.out.println("随机生成的公钥为:" + keyMap.get(0));
        System.out.println("随机生成的私钥为:" + keyMap.get(1));
        String messageDe = decrypt("c2Ww89yH4lmUQio2qkkYg8GL35NxX1zHusRKjFAmYuqZo1EUYOzKyky91rfhdZxmMPz1vHev8vz4mBNxqF6Tc4EPPIwKhsKPHI2Tgzcoa4GlQqJlXOrD4tCJxnFYBBbdqQ+WIJd0fGyJS11/daaeqhCPrJEmJohB1Or2oe2o9fw=");
        System.out.println("还原后的字符串为:" + messageDe);
    }

    /**
     * 随机生成密钥对
     *
     * @throws NoSuchAlgorithmException
     */
    public static void genKeyPair() throws NoSuchAlgorithmException {
        // KeyPairGenerator类用于生成公钥和私钥对，基于RSA算法生成对象
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
        // 初始化密钥对生成器，密钥大小为96-1024位
        keyPairGen.initialize(1024, new SecureRandom());
        // 生成一个密钥对，保存在keyPair中  得到私钥
        KeyPair keyPair = keyPairGen.generateKeyPair();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        // 得到公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        String publicKeyString = new String(Base64.encodeBase64(publicKey.getEncoded()));
        // 得到私钥字符串
        String privateKeyString = new String(Base64.encodeBase64((privateKey.getEncoded())));
        // 将公钥和私钥保存到Map   0表示公钥   1表示私钥
//        keyMap.put(0, publicKeyString);
//        keyMap.put(1, privateKeyString);
    }

    /**
     * RSA公钥加密
     *
     * @param str       加密字符串
     * @param publicKey 公钥
     * @return 密文
     * @throws Exception 加密过程中的异常信息
     */
    public static String encrypt(String str, String publicKey) throws Exception {
        //base64编码的公钥
        byte[] decoded = Base64.decodeBase64(publicKey);
        RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
        //RSA加密
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, pubKey);
        String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes()));
        return outStr;
    }

    /**
     * RSA私钥解密
     *
     * @param str        加密字符串
     * @return 铭文
     * @throws Exception 解密过程中的异常信息
     */
    public static String decrypt(String str) {
        try {
            //64位解码加密后的字符串
            byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
            //base64编码的私钥
            byte[] decoded = Base64.decodeBase64(keyMap.get(1));
            RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
            //RSA解密
            Cipher cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.DECRYPT_MODE, priKey);
            String outStr = new String(cipher.doFinal(inputByte));
            return outStr;
        } catch (Exception e) {
            log.debug("decrypt failure......" + e.getMessage());
            return null;
        }
    }
}
